Description (Adapted from Application): Bdellovibrios are procaryotic predators which prey on certain susceptible Gram-negative bacilli. Including among the prey bacteria are human such as Vibrio cholerae, V. vulnificus, V. parahaemolyticus, Pseudomonas species, and E. coli. Based on observations in laboratory vessels that bdellovibrios reduce the population of its prey, a logical question is, does the predatory bacterium play some role in the control of pathogenic bacterial populations in nature? Adequate experimentation to resolve this questions has not been reported. This is largely due to the limitation in technology to detect and monitor the predator in the environment. The only method currently available for the specific detection of bdellovibrios is the culture technique, which has substantial limitations. The aim of this proposal is to develop a genetic probe and PCR primers which can be used for the specific detection of bdellovibrios in aquatic environments and to use these to study the interaction of the predatory bacteria with human pathogens in nature. Initial efforts will be made to identify unique sequences among known nucleic acid sequences for bdellovibrios and to test these as probes and as PCR primers. Using these tools, the investigators will evaluate the numbers of predators in the aquatic environment and the predominant types of strains/species present. The objectives are: (1) to identify and synthesize specific DNA oligonucleotide sequences for use as selection probes and PCR primers; to identify candidate genomic restriction fragment sequences for use as DNA probes and produce them by cloning and/or PCR synthesis; to identify candidate rRNA sequences and construct rRNA probes; (2) to examine the use and sensitivity of PCR to detect bdellovibrios in laboratory microcosms and environmental samples; (3) to examine the suitability of rRNA probes to detect and enumerate cells of bdellovibrios; (4) to evaluate the use of probes to detect bacteria infected; and (5) to examine the use of genus and species- specific probes to confirm the identification of plaques (colonies) of bdellovibrios recovered on culture medium. This study will contribute to the rapidly growing research enterprise at MSU. It will establish research collaborations between MSU and major research institutions: University of Maryland-Baltimore; VA Medical Center, Baltimore; Center of Marine Biotechnology. Students and faculty at MSU will benefit from ancillary involvement. In this way the project conforms to the goals of the SCORE program.